The Eustachian tube is a hollow tube that originates in the back of the nose and connects the nasal cavity to the middle ear space. The middle ear space is the hollowed out portion of the skull bone that contains the hearing mechanism, which is covered by eardrum on one side and cochlea on the other side. The Eustachian Tube provides ventilation, drainage and protection of mid ear against reflux, microorganisms, excessive sound pressure and pressure changes in pharynx. In adults, the Eustachian tube is approximately 35 mm long and approximately 3 mm in diameter. The first part of the Eustachian tube is supported by cartilage and the last part that is close to the middle ear space is located inside the bone structure. The lining tissue of the Eustachian tube is similar to tissue that covers the nasal cavity and responds to external stimulants just as nasal tissue does.
The main function of the Eustachian tube is to provide ventilation to the middle ear space, ensuring that its pressure remains at slightly negative but close to ambient air pressure. Another function of the Eustachian tube is to drain secretions and debris from the middle ear space. Several small muscles located in the back of the throat and palate control the opening and closing action of the tube. Typical muscular actions like swallowing and yawning cause contractions of these muscles and activate Eustachian tube function time to time to achieve its pressure regulation function.
Eustachian tube is normally closed most of the time to prevent contaminants contained in the nasal cavity to reach the middle ear space cavity. Disorders of ET are basically either “dilatory” type (failure to open adequately) or “patulous” type (failure to maintain tube closed at rest). Dysfunction of an Eustachian tube makes the tube always open and this condition is called a “patulous” Eustachian tube. Patients with “patulous” dysfunctional Eustachian tube suffer from frequent, chronic ear infections. A more common form of the Eustachian tube dysfunction causes partial or complete blockage of the Eustachian tube which cause sensations of popping, clicking, and ear fullness as well as moderate to severe ear pain associated with the condition.
Many people suffer from Eustachian Tube (ET) dysfunction and this condition affects quality of their life. There have been many different attempts over the history to solve the problem of ET dysfunction. Most devices developed are in the form of tubes or similar inserts which are inserted into Eustachian tube to keep it open and provide ventilation. Patents and applications; WO 2009/001358, WO 2006/049131, US patent US 2009/0099573, WO 2005/082303, U.S. Pat. No. 4,015,607 can be cited in this category which more or less achieve the purpose using this method. U.S. Pat. No. 4,888,017 proposes a different approach by providing an inflatable gadget to open the Eustachian tube momentarily by patient applying pressure manually to activate the device which forces open the ET tube. Another remedy used by surgeons to rectify Eustachian tube dysfunction ailment is to fix a grommet on the eardrum of the patient to provide ventilation for the middle ear cavity. These methods mentioned above have some complications. Most patients report that insert devices used for keeping Eustachian tube open simply do not remain in place for long time and provide solution only for a limited time. Grommets (rings) placed on ear drums also tend to fall after several weeks. Additionally, keeping the ET tube always open solves one problem but causes secondary problems by providing an open path for liquid and external contaminants to flood the mid ear cavity.
Patents like WO 01/43653 and WO 2008/079476 provides alternative techniques of surgical manipulation of ET tube by laser and radio frequency techniques to remedy the problem of Eustachian Tube Dysfunction related complications. Overall, many humans as well as animals are afflicted with ET dysfunction problem.
The present invention attempts to solve the problem with a different mechanism which activates muscles of the ET. The muscles surrounding the ET tube activate the opening/closing action of the ET valve. As R. Leuwer writes in an article titled “Mechanics of Eustachian tube” published in “Chronic Otitis Media. Pathogenesis-Oriented Therapeutic Management”, pp 129-134 edited by B. Ars (2008 Kugler Publications), Eustachian tube has a complex muscular compliance which involves influence of tensor veli palatine muscle, levator veli palatine muscle and medial pterygoid muscle. Most researchers agree that tensor veli palatini and levator veli palatine are primary activators of the Eustachian tube whereas medial pterygoid muscle has secondary influence on function of the ET by changing the position of the ET and the veli muscles mentioned above.
In 1979, Cantekin et. al reported in an article published in Ann Otol Rhinol Laryngol. 1979 January-February; 88(1 Pt 1):40-51 that they have conducted a series of experiments with Rhesus monkey and observed that Eustachian Tube (ET) tube action is initiated by muscles surrounding the ET tube. This, indeed has proven that Eustachian tube is not a simple tube and its function can be controlled by a series of coordinated activation of the surrounding muscles.